Addiction in pregnancy is an important health problem due to the increased incidence of obstetrical and medical complications in these women and the high rate of prematurity and other untoward sequelae in the infants. Too little is presently known about how best to prevent and treat the adverse sequelae of addiction in the mother and infant. A comprehensive treatment program including medical and addictive care has been developed at our hospital with the aim of defining the effects on long and short term outcome of patients enrolled in the program vis a vis untreated addicts and to study the differential effects of various treatments for the neonatal abstinence syndrome. Initial findings indicate that comprehensive care of addicts may significantly reduce the morbidity and mortality to both mother and infant, and that opiate drugs are more effective than sedatives for treating the abstinence syndrome in newborns. The following patient groups have been defined in order to compare statistically the effects of various drugs and the effects of treatment: Group A: Heroin-dependent, no prenatal care; Group B: Non- drug dependent, no prenatal care; Group C: Methadone-dependent, adequate psychosocial and prenatal care; Group D: Non-drug dependent, adequate prenatal care; Group E: Methadone-dependent, inadequate prenatal care. Since an objective of a comprehensive approach is to decrease long-term neurological sequelae to the infant which are so common in these high-risk pregnancies, continual pediatric, neurological, developmental and psychological follow-up evaluation of the infant may help define the long-term effects of maternal drug abuse and passive narcotic addiction upon the infant. With the realization of the multiplicity of medical and psychological problems of the pregnant addict, it appears that a comprehensive care approach encompassing the physical and mental needs of both mother and infant may succeed in preventing some of the serious sequelae, as well as provide a background from which valuable physiological, developmental, behavioral, nutritional and genetic parameters in this mother-infant diad may be studied.